DRF框架

柔情只为你懂 2022-10-29 01:49 141阅读 0赞

> 在开发web应用中，通常有两种应用模式：
> 
>  *  前后端不分离
>  *  前后端分离
> 
> 下面介绍的时前后端分离情况下时，运用`django-rest-framework`框架实现数据传递

## `django-rest-framework`安装与配置 ##

*  安装：`pip install django-rest-framework`
 *  [官方文档][Link 1]
 *  添加`rest_framework`应用
    
        INSTALLED_APPS = [
            'rest_framework',
        ]

## `Serializer`序列化器 ##

> 序列化器的作用：
> 
>  *  进行数据校验
>  *  对数据对象进行转换

示例：

书籍–>英雄（一对多关系）

# model.py模型类
    
    from django.db import models
    
    
    class BookInfo(models.Model):
        name = models.CharField(max_length=200, verbose_name='书籍名称')
        info_date = models.CharField(max_length=500, blank=True, verbose_name='相关信息')
        create_time = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')
    
        class Meta:
            db_table = 'tb_book'
            verbose_name = '书籍信息'
            verbose_name_plural = verbose_name
    
        def __str__(self):
            return self.name
    
    
    class HeroInfo(models.Model):
        hero_name = models.CharField(max_length=100, verbose_name='英雄名字')
        hero_info = models.CharField(max_length=200, verbose_name='英雄事迹')
        book = models.ForeignKey(BookInfo, on_delete=models.CASCADE, related_name='book_hero', verbose_name='所属书籍')
    
        class Meta:
            db_table = 'tb_hero'
            verbose_name = '英雄信息'
            verbose_name_plural = verbose_name
    
        def __str__(self):
            return self.hero_name

*  新建`serializer.py` (`apps->books->serializer.py`)
    
        from rest_framework import serializers
        from .models import BookInfo
        
        
        class HeroSerializer(serializers.Serializer):
            hero_name = serializers.CharField()
            hero_info = serializers.CharField()
            # 返回序列化关联对象的字符串表示方式（即__str__方法的返回值）
            book = serializers.StringRelatedField()
            # 返回序列化关联对象的主键
            # book = serializers.PrimaryKeyRelatedField(read_only=True)
        
        
        class BookSerializer(serializers.Serializer):
            name = serializers.CharField(max_length=100, min_length=2)
            info_date = serializers.CharField(max_length=200, default="")
            book_hero = HeroSerializer(many=True, read_only=True)
        
            # 单个字段验证
            def validate_name(self, value):
                if value == 'python':
                    raise serializers.ValidationError('书籍名称不能为python')
                return value
        
            # 多个字段验证
            def validate(self, attrs):
                if attrs['info_date'] == 'bbb':
                    raise serializers.ValidationError('字段名错误')
                return attrs
    
    **选项参数**：
    
    <table> 
     <thead> 
      <tr> 
       <th>参数名称</th> 
       <th>作用</th> 
      </tr> 
     </thead> 
     <tbody> 
      <tr> 
       <td><strong>max_length</strong></td> 
       <td>最大长度</td> 
      </tr> 
      <tr> 
       <td><strong>min_lenght</strong></td> 
       <td>最小长度</td> 
      </tr> 
      <tr> 
       <td><strong>allow_blank</strong></td> 
       <td>是否允许为空</td> 
      </tr> 
      <tr> 
       <td><strong>trim_whitespace</strong></td> 
       <td>是否截断空白字符</td> 
      </tr> 
      <tr> 
       <td><strong>max_value</strong></td> 
       <td>最小值</td> 
      </tr> 
      <tr> 
       <td><strong>min_value</strong></td> 
       <td>最大值</td> 
      </tr> 
     </tbody> 
    </table>
    
    #### 通用参数： ####
    
    <table> 
     <thead> 
      <tr> 
       <th>参数名称</th> 
       <th>说明</th> 
      </tr> 
     </thead> 
     <tbody> 
      <tr> 
       <td><strong>read_only</strong></td> 
       <td>表明该字段仅用于序列化输出，默认False</td> 
      </tr> 
      <tr> 
       <td><strong>write_only</strong></td> 
       <td>表明该字段仅用于反序列化输入，默认False</td> 
      </tr> 
      <tr> 
       <td><strong>required</strong></td> 
       <td>表明该字段在反序列化时必须输入，默认True</td> 
      </tr> 
      <tr> 
       <td><strong>default</strong></td> 
       <td>反序列化时使用的默认值</td> 
      </tr> 
      <tr> 
       <td><strong>allow_null</strong></td> 
       <td>表明该字段是否允许传入None，默认False</td> 
      </tr> 
      <tr> 
       <td><strong>validators</strong></td> 
       <td>该字段使用的验证器</td> 
      </tr> 
      <tr> 
       <td><strong>error_messages</strong></td> 
       <td>包含错误编号与错误信息的字典</td> 
      </tr> 
      <tr> 
       <td><strong>label</strong></td> 
       <td>用于HTML展示API页面时，显示的字段名称</td> 
      </tr> 
      <tr> 
       <td><strong>help_text</strong></td> 
       <td>用于HTML展示API页面时，显示的字段帮助提示信息</td> 
      </tr> 
     </tbody> 
    </table>

## 五个扩展类使用 ##

> 五个扩展类（配合GenericAPIview使用）继承自object

示例：`ListModelMixin, CreateModelMixin, DestroyModelMixin, UpdateModelMixin`

from rest_framework.mixins import ListModelMixin, CreateModelMixin, DestroyModelMixin, UpdateModelMixin
    
    class BooksView(GenericAPIView, ListModelMixin, CreateModelMixin):
        queryset = BookInfo.objects.all()
        serializer_class = BookSerializer
    
        def get(self, request):
            return self.list(request)
    
        def post(self, request):
            return self.create(request)
    
    
    class BookUD(GenericAPIView, UpdateModelMixin, DestroyModelMixin):
        queryset = BookInfo.objects.all()
        serializer_class = BookSerializer
    
        def put(self, request, pk):
            return self.update(request, pk)
    
        def delete(self, request, pk):
            return self.destroy(request, pk)

## `ListCreateAPIView,RetrieveUpdateDestroyAPIView`使用 ##

示例：

from rest_framework.generics import ListCreateAPIView, RetrieveUpdateDestroyAPIView
    
    # 展示和创建模型
    class BooksView(ListCreateAPIView):
        queryset = BookInfo.objects.all()
        serializer_class = BookSerializer
    
    # 获取单一对象,更新和删除模型
    class BookRED(RetrieveUpdateDestroyAPIView):
        queryset = BookInfo.objects.all()
        serializer_class = BookSerializer

*  获取单一数据
    
    ![image-20210207152436144][]
 *  注意：路由配置参数必须为`pk`
    
        path('book/<str:pk>', views.BookRED.as_view(), name='bookRED')

## 两个基本视图集 ##

![image-20210207153132708][]

class Books(ViewSet):
        def list(self, request):
            books = BookInfo.objects.all()
            ser = BookSerializer(books, many=True)
            return Response(ser.data)
    
        def create(self, request):
            data = request.data
            ser = BookSerializer(data=data)
            ser.is_valid()
            ser.save()
            return Response(ser.data

# url.py配置
    path('', views.Books.as_view({ 'get': 'list', 'post': 'create'}, name='books'))

[Link 1]: https://www.django-rest-framework.org/
[image-20210207152436144]: /images/20221024/9b6cab720a654b9290570797071dc39e.png
[image-20210207153132708]: /images/20221024/8837185e15834e83b7bcd1ade65cb472.png